Is there such a phrase in your language? (Or some other language that you know.) And what does it literally sais? Please, please contribute! (Other comments, links, and relevant pictures are welcomed.)

I got interested in this saying in the context of studying noise-models for fault-tolerant computation and specifically spontaneous error-synchronization, it can also serve us also in the context of financial collapses.

In British English, I think “it never rains but it pours” would be the equivalent. But it may be a regional phrase (it’s notably untrue for much of the British Isles), and Louigi has an interesting point. English is spoken in lots of countries where rain is a rare and good thing, and the sense would be positive.

Shakespeare’s version has never really caught on:
“When sorrows come, they come not single spies,
But in battalions.”

Slightly unrelated, but it’s interesting to note how some phrases have the same meaning, but use different objects in the phrase. For example, I don’t know why the equivalent of “shooting oneself in the foot” in many Indo-European languages has no mention of a gun, but instead an axe or a hoe. I guess it’s because guns are too recent for these languages, but English is a newer language?

In Hindi, the line says ‘Gharibi me aataa geela.’ It is translated as ‘You are poor, and the bread dough you prepared has excess water.’ (The implication is that Misfortune comes in packages. You do not have any more flour left to tighten the dough – bread cannot be made any more and you will have to go hungry.)

In Finnish:
“Ei kahta ilman kolmannetta.” ~ “No two (accidents or other cases of bad luck), without the third.”
and related, although with a different sense:
“Vahinko ei tule kello kaulassa.” ~ “An accident will not come with a bell tied to its neck.” (like cows used to have.)

German has a very particular analogue: “Das Gesetz der Serie”. This is the title of a work on coincidences by Paul Kammerer, but is a common social phrase in Germany when multiple things go wrong. There is a recent serious mathematical analogue in ergodic theory, summarized in this Scholarpedia article, and by the authors Downarowicz and Lacroix themselves in this readable page.

Hungarian: A baj nem jár egyedül. According to the above, the exact same expression as in Russian, Croatian, Czech, Latvian, Portuguese, French, German, Swedish, Danish, Chinese. The old Greek is almost the same, maybe not exactly. But the Latin is different. Is it from the Bible?

There’s a related Hungarian saying, similar to the Rumanian one: Szegény embert az ág is húzza. = A poor man is held back even by the branches.